Refactors how quic packets get handled: the actual tunnels now live in
tunnel.hpp's TunnelManager which holds and manages all the quic<->tcp
tunnelling. service::Endpoint now holds a TunnelManager rather than a
quic::Server. We only need one quic server, but we need a separate quic
client instance per outgoing quic tunnel, and TunnelManager handles all
that glue now.
Adds QUIC packet handling to get to the right tunnel code. This
required multiplexing incoming quic packets, as follows:
Adds a very small quic tunnel packet header of 4 bytes:
[1, SPORT, ECN] for client->server packets, where SPORT is our
source "port" (really: just a uint16_t unique quic instance
identifier)
or
[2, DPORT, ECN] for server->client packets where the DPORT is the SPORT
from above.
(This also reworks ECN bits to get properly carried over lokinet.)
We don't need a destination/source port for the server-side because
there is only ever one quic server (and we know we're going to it when
the first byte of the header is 1).
Removes the config option for quic exposing ports; a full lokinet will
simply accept anything incoming on quic and tunnel it to the requested
port on the the local endpoint IP (this handler will come in a following
commit).
Replace ConvoTags with full addresses: we need to carry the port, as
well, which the ConvoTag can't give us, so change those to more general
SockAddrs from which we can extract both the ConvoTag *and* the port.
Add a pending connection queue along with new quic-side handlers to call
when a stream becomes available (TunnelManager uses this to wire up
pending incoming conns with quic streams as streams open up).
Completely get rid of tunnel_server/tunnel_client.cpp code; it is now
moved to tunnel.hpp.
Add listen()/forget() methods in TunnelManager for setting up quic
listening sockets (for liblokinet usage).
Add open()/close() methods in TunnelManager for spinning up new quic
clients for outgoing quic connections.
